Generally, there are three modes for accessing internet, i.e., a dial-up mode via a telephone line, a Cable Modem (CM) mode via a cable television line, and an Ethernet mode via a twisted pair. In a process of accessing internet in each of these modes, a special modem and an access port are required, which results in a high cost and inconvenience.
With a continuous development of power line communication technology, a high Internet connection speed of 4.5 Mbps to 45 Mbps can be provided to users, which allows the user to browse web pages, make calls and watch movies online. Therefore, networks of data, voice, video and power are integrated together. The full name of the power line communication is Power Line Carrier (PLC) communication, which refers to a special communication mode for transmitting voices or data by using a high voltage power line, a medium voltage power line or a low voltage distribution line as an information transmission medium.
During the implementation of the present disclosure, the inventors found that although the power line communication technology is continuously improved, a frequency selective fading due to a multi-path effect and a large-scale fading due to a line loss exist on a power line channel in the existing power line communication system. Thus, a channel between two PLC modems with a very short physical distance may be in a deep fading area. In addition, due to the large-scale fading, the signal between two PLC modems with a long distance has energy less than a minimum receiving threshold. Furthermore, various strong interferences exist on the power line channel. All these problems lead to a low signal transmission quality and a low system reliability of the existing power line communication system.